I remember being a kid and thinking that animals that bend down to drink from a pond must be forcing the water to travel up their esophagus. Hmm, I wonder if humans can do that. So I filled my mouth with water, did a head stand, then swallowed. Yes, no problem. Newfound respect for my body that day.
My 8th grade science teacher showed us this back in 1960: he had one of us do a handstand and drink water from a cup using a straw with no choking or gagging.
Sure, but it still means that your body has to force the food/drink down (er, or "in" if you're in space, I guess) rather than just letting gravity do the work.
Entertaining the silly argument we have gotten ourselves into: Solid food does not just fall into our stomachs normally, the processes of swallowing is quite complex and involves mechanically pushing food down through peristaltic waves in multiple phases. Liquids are another story though.
It is entirely baseless of course, but I imagine that the difference for solid foods between a the small aid of gravity, unable to make the food move on its own, and having no aid is probably significantly less than the difference between no aid and an opposing force. And yet in either case, the process of swallowing remains exactly the same, always having to force the food down with the same motion but different effort.
Your story reminds me of this segment from Mr. Wizard that I saw as a child. This kid eats an apple while doing a hand stand, and I remember being amazed by it.
